Toshio Kawai

PACS: a parallel microprocessor array for scientific calculations

Pacs-32 is a prototype supercomputer used for a broad range of scientific calculations. It has a synchronizable MIMD processor array, and on the basis of this facility, it provides efficient nearest neighbor communication. Processors are combined into a rectangular array with endaround connections, and can synchronize at user-specified points with little overhead. The hardware has been constructed with 32 processors, and the operating software includes a high-level language. The Pacs-32 system has performed in a number of applications, such as Poisson equation solving, nuclear reactor calculation, aerodynamics, Monte Carlo simulation of plasma particles, and molecular dynamics modeling in solid state physics. The processor efficiency measure ranges from 78 percent through 99 percent in these applications. 12 references.

QCDPAX: A parallel computer for lattice QCD simulation

Abstract QCDPAX, a highly parallel processor array specially designed for the numerical simulation of lattice gauge theories, currently under construction at University of Tsukuba, is described. The machine is planned to incorporate several hundred processing units, interconnected in a nearest-neighbor-mesh. This project is funded with about two million dollars by the Japanese government from 1987 FY to 1989 FY.

Cluster formation by inelastically colliding particles in one-dimensional space

Inelastically colliding particles moving in one-dimensional space are found to form clusters, each of which consists of particles with identical coordinates and velocities. There exists a critical size of a cluster, above which the cluster grows indefinitely by absorbing a colliding particle as if the collision were completely inelastic (rebound coefficient e = 0. It is experimentally found that when e = 0, the expected number of n-particle clusters is 1n, and the average number of final clusters 〈M〉 is 〈M〉 = ΣNn 11n, where N is the number of the particles in the system.

A new measure of local temperature distribution in non-equilibrium molecular dynamics simulation of friction

Analysis methods of energy dissipation mechanisms in the non-equilibrium molecular dynamics simulation of friction were studied. A spatial distribution of local quasi-temperature, defined by averaging over time, was found to be a potentially convenient measure of the heat generation and transport accompanying friction or, more generally, in microscopic non-equilibrium systems characterized by strong spatial and slight temporal inhomogeneities. Moreover, the local quasi-temperature is applied to the visualization of modes in which a steady spatial distribution is formed by wearless friction and then collapses owing to wear with the passing of time.

Hadron masses and decay constants with Wilson quarks at β=5.85 and 6.0

We present results of a high statistics calculation of hadron masses and meson decay constants in the quenched approximation to lattice QCD with Wilson quarks at

Equipartition of particles forming clusters by inelastic collisions

\beta=

Numerical analysis of trajectories of a quantum particle in two-slit experiment

5.85 and 6.0 on

Electromagnetic plane waves with parallel electric and magnetic fields E∥H in free space

24^3 \times 54

An Inelastic Collision Model for the Evolution of "Planetary Rings"

lattices. We analyze the data paying attention in particular to the systematic errors due to the choice of fitting range and due to the contamination from excited states. We find that the systematic errors for the hadron masses with quarks lighter than the strange quark amount to 1 --- 2 times the statistical errors. When the lattice scale is fixed from the

Non-Transverse Electromagnetic Waves with Parallel Electric and Magnetic Fields

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